Equipment, supplies and other items may be efficiently delivered to a desired location by dropping them from aircraft and using parachutes to slow their descent to bring them safely to ground. This method of deployment removes the need for the aircraft to land, which might not be possible or convenient, depending on the terrain and availability of a suitable runway and ground support. The parachute guidance system may be used to steer the parachute and its cargo towards a desired location during its flight. An example of an aerial delivery device having a parachute guidance system is described in U.S. Pat. No. 7,059,570 to Strong. The delivery device includes an overloaded ram-air drogue parachute that is controlled by a guidance system to steer the payload towards an intended target. At a selected altitude, a round, recovery parachute is activated, the drogue parachute collapses and the payload descends the remaining distance under the recovery parachute. The guidance system includes a control unit that is suspended from the drogue parachute and includes two control lines connected to left and right steering lines of the parachute. The control lines are wound on a respective winch spool each driven by a motor which lets the control lines in and out thereby controlling the steering lines and the direction of the parachute. The guidance control unit is connected to a mounting plate which is connected to the parachute suspension lines by risers. The lower part of the mounting plate has a connector for connecting a payload therethrough via a riser. The control unit also controls the deployment of the recovery parachute and for this purpose, includes a motorized winch spool that pulls in the rip cord of the recovery parachute once the payload has reached the desired altitude. The recovery parachute, which is not steered, then descends the remaining distance to the ground.
Another example of a steerable parachute and control system is disclosed in CA 2,469,680. The parachute system includes both a ram-air drogue parachute and a round recovery or landing parachute. During descent, the control system steers the ram-air parachute to a position substantially overhead of the target and subsequently controls the ram-air parachute to adopt a spiral descent pattern. At a predetermined height above ground, the guidance parachute is released and automatically deploys the landing parachute by static line. Thereafter, the unsteered landing parachute and payload continues its descent to the ground.